Plants

Question 1

Function of waxy cuticle

Answer 1

Water resistant- decreases water loss from evaporation and water glides off

Question 2

Function of upper epidermis

Answer 2

Thin, protective and transparent to allow free passage of light

Question 3

Function of palisade layer

Answer 3

Compact cell, layer full of chloroplasts, dense packing allows the maximum amount of light energy absorbed

Question 4

Function of spongy mesophyll

Answer 4

Gaps allow fast diffusion of gases

Question 5

Function of the vein

Answer 5

Xylem Carrie’s minerals and water from the roots
Phloem Carrie’s nutrients (sucrose) from the leaves

Question 6

Function of guard cell

Answer 6

Controls stomata opening and closing

Question 7

Function of stoma

Answer 7

A gap that allows gases through CO2 and H2O and O2

Question 8

Stomata control

Answer 8

Water entering the guard cells by osmosis causes the cells to become turgid. This results in the pushing away and there by opening the stoma. In low water conditions, the water in the guard cells leave by osmosis. Guard cells become flaccid and close the stoma.

Question 9

Requirements for photosynthesis

Answer 9

• the availability of light
• the presence of a pigment to absorb the light
• a supply of carbon dioxide and water
• a temperature suitable for enzyme activity

Question 10

Why do plants need nitrate

Answer 10

Plants need nitrate to be able to join with glucose to produce amino acids that are then used to form proteins . A shortage of nitrate, the plant will reduce it rate of photosynthesis because it will need fewer sugars to make amino acids. Stunted growth, yellowing leaves, poor seed development

Question 11

Testing for starch

Answer 11

1. Collect leaf samples: A) has been covered with black paper
   B) has been left exposed
2. Dip the leaves in boiling water - kills the cells to stop metabolic activity- soften up the leaf
3. Dip the boiled leaves in ethanol- chlorophyll is soluble in ethanol so it leaves the leaf - will look brown
4. Dip the leaves in water again
5. Add iodine to the leaf

Hypothesis- A) covered leaf: negative ( iodine remains brown)

                 B) exposed leaf: positive ( iodine turns starch black/ blue)

Question 12

What is the use of the availability of light

Answer 12

Light provides the energy that drives photosynthesis by splitting water molecules

Question 13

Light energy absorbed by a plant depends on what

Answer 13

• the intensity of the light source
  -v the wavelength of the light
• the length of time that the light is available

Question 14

What is the use of cholorophyll

Answer 14

Chlorophyll is essential for the absorption of light energy. The synthesis of chlorophyll requires magnesium ions, which must be supplied from the soil

Question 15

What is the use of carbon dioxide

Answer 15

Carbon dioxide concentration has a major influence on the rate of photosynthesis because it is the substrate that is in shortest supply there is almost always enough water

Question 16

What does temperature affect

Answer 16

Temperature affects the rate of enzyme activity. A 10C rise in temperature can cause a doubling in the rate of enzyme activity, higher temperatures cause denaturation. This is important both on leaves, enzymes involved directly in photosynthesis and in roots involved in active transport of mineral ions

Question 17

Equation of photosynthesis

Answer 17

6CO2 + 6H2O ——-> 6O2 + C6H12O6

Question 18

Factors of photosynthesis

Answer 18

• temperature
• light intensity
• CO2 concentration
• surface areas of leaves
• stomatal density

Question 19

Factor of temperature on photosynthesis

Answer 19

Overall kinetic energy increases so substrates and enzymes meet and react more often. The limit of reaction increase is around 50C since enzymes denature

Question 20

how to measure the rate of photosynthesis

Answer 20

A) Underwater set up with pondweed
B) Potometer

Question 21

How do you use the method of underwater set up with pondweed

Answer 21

bubbles/time = rate
volume of O2/ time = rate

Question 22

how to use the method of potometer

Answer 22

Δd/t = rate
measure how far the bubble moves in given amount of time

Question 23

why is transpiration rate related to photosynthesis rate

Answer 23

water is needed for photosynthesis which is brought by the transipiration stream. Photosynthesis also needs CO2 which is obtained from stomata. Open stomata causes loss of water vapour which speeds up the transpiration rate

Question 24

what are the indicator for photosynthesis experiments

Answer 24

• hydrogen carbonate indicator
• lime water indicator

Question 25

what is the hydrogen carbonate indicator

Answer 25

- normally a pink hue - in acidic conditions turns yellow -in more alkali environment it turns violet/ purple

Question 26

what is the limewater indicator

Answer 26

-normally transparent/ colourless - with CO2 turns milky white/ opaque

Question 27

what are the result when the leaf is exposed to light

Answer 27

photosynthesis takes the CO2 thereby reducing acidity CO2 + H2O -----> carbonic acid

Question 28

hat are the results when the leaf is in darkness

Answer 28

respiration and no photosynthesis increases CO2 concentration more acidic

Question 29

all nutrients in plants

Answer 29

carbon nitrogen phosphorus potassium magnesium

Question 30

what does the carbon nutrient do

Answer 30

it is used to make glucose into starch and is also used for all organic molecules

Question 31

what does the nitrogen nutrient do

Answer 31

it is converted in soil into ammonia and then nitrates. Nitrates used to make amino acids and nucleotides for DNA & RNA

Question 32

what does the phosphorous nutrient do

Answer 32

in phosphate form to make nucleotides

Question 33

what does the potassium nutrient do

Answer 33

for protein production

Question 34

what does the magnesium nutrient do

Answer 34

used for chlorophyll production

Question 35

examples of natural fertilizers

Answer 35

manure and compost

Question 36

Pros and Cons of natural fertilizers

Answer 36

Pros- sustainable, no harmful chemicals involved Cons- odor, time needed, nutrient/ mineral component not consistent

Question 37

Pros and Cons of chemical fertilizers

Answer 37

pros- easily and readily accessible, know exactly how much of each nutrient/ mineral you are adding to you fild/ crop cons- easy to over use, top layer gets washed away, run off causes algal bloom( eutrification), more expensive

Question 38

whats good about greenhouses

Answer 38

are transparent to allow light through and light energy is absorbed and released as thermal energy which heats up the greenhouse

Question 39

hat are paraffin lamps

Answer 39

you install paraffin lamps in greenhouses to release CO2 and increase the concentration beyond atmosphere concentrations

Question 40

what is the compensation point

Answer 40

when the rate of photosynthesis is equal to the rate of respiration

Question 41

what should be controlled in greenhouses

Answer 41

intensity- higher intensity leads to more photosynthesis until some other limiting factors intervenes quality- photosynthesis is most efficient at red and blue wavelengths: white light contains some wavelengths (green) which are not useful duration- if fruit is desired product, the plant must flower: flowering is controlled by day length (the duration of light in a 24- hour period) - artificial lighting systems are more controllable

Question 42

explain why temperature has effect on the rate of photosynthesis

Answer 42

temperature increase leads to an increase of kinetic energy in substrates allowing for them to have successful collisions more often. However, when the temperature increases too much, the enzymes denature causing the plant to die

Question 43

discuss the advantages of growing crops in glasshouses

Answer 43

- light goes through which plants need + heat gets trapped - can protect from pests - can control carbon dioxide concentration (parassin lamps) - can control temperature regardless of the season (heaters) - can control water supply and minerals, nutrients - hydroponides (when you grow plants in water)

Question 44

Describe how the palisade layer is adapted to maximize photosynthesis

Answer 44

The palisade layer is compact, it has a high chloroplast concentration, it is located near the surface and therefore has access to light and its large central vacuoles, presses chlorplasts on the edge, all of which help maximize photosynthesis

Question 45

Describe the function of stomata

Answer 45

they are gaps in leafs located next guard cells that allow gases to enter and exit the cell (gas exchange). They open depending on the plants needs and close when in dry conditions to limit water loss and prevent wilting

Question 46

./explain the effects of nitrate ion deficiency on plant growth

Answer 46

stunted growth, yellowing leaves, reduced seed and production and poor root developement which makes plants susceptible to disease